1. Field of the Invention
This invention relates to a rotary valve, such as a butterfly valve, ball valve or cock valve, that is fitted to a pipe for passing a fluid, such as service water, hot water, cold water, cooling water or air, to an air conditioning device, plaint device or factory device. More particularly, the invention relates to a rotary valve having a main valve body modulated as a common component, thereby adapting other component parts of various types for attachment to and detachment from the main valve body and giving rise to any one of various valves.
2. Description of the Prior Art
FIG. 24 is a front view illustrating one example of the ordinary butterfly valve that is in popular use among other rotary valves. This butterfly valve comprises a cylindrical body 1, a rubber seat ring 2 disposed in the body 1, a disk 3 disposed in the seat ring 2 so as to rotate therein with a stem and produce opening and closing motions. The stem is disposed in a long shaft cylinder 4 projecting in the body 1. A lever-operating device 6 (or a gear-operating device or an electric, pneumatic or hydraulic actuator) is fastened with a bolt 7 and a nut 8 onto a flange 5 formed at the upper end of the shaft cylinder 4. This butterfly valve is a long neck one that particularly conforms to the need for coating with a heat insulating material or the need for other piping. A short neck butterfly valve having a short shaft cylinder is also available. The butterfly valves of these kinds are completed in their entirety by incorporating pertinent components parts therein. The valve products finished in conformity to individual applications are delivered to the market.
One of the inventors of the present invention proposed a non-neck butterfly valve as a version with a low frequency of producing opening and closing motions in actual use (JP-A08-312795).
Thus, the conventional butterfly valves have been completed as products of individual types, i.e. various valves conforming to the needs for pipes and the environment of installation, to satisfy the users"" demands.
By the necessity for conforming to varying market demands, therefore, the number of parts has been naturally increasing and further, the demands for storage and management of parts have been growing so as to entail additional cost. Even from the viewpoint of saving resources and respecting economy, the desirability of developing a rotary valve, such as a butterfly valve, having fulfilled such tasks has been finding growing recognition.
As shown in FIG. 24, the lever-operating device 6 mounted on the rotary valve, for example, is fastened to the flange 5 with the bolt 7 and nut 8. In this case, a clearance will exist between the inside diameter of a hole 5a (FIG. 25) of the flange 5 and the outside diameter of the bolt 7.
For this reason, the butterfly valve, on generating a twist or a rotational torque, causes its position to deviate in a size proportionate to the clearance and loosen the bolt 7. In the rotary valve of this structure, if the component members are coupled with bolts, they will possibly give rise to a slight deviation and particularly degrade the accuracy of the position for closing the valve body.
With a view to solving the conventional problems, one object of the present invention is to a rotary valve having a main valve body modulated as a common component part. This allows parts other than the main valve body to be exchanged in conformity with the need for pipes and the environment of installation, with the main body part mounted on the pipe. As a. result, it is possible to attain a reduction in cost, improve the economy exceptionally and consequently enhance the work execution property. This further exalts the accuracy of closure of the valve by infallibly coupling such other parts with the main body part without possibly inducing any deviation of the sites of connection.
To attain the above object, the present invention provides a rotary valve that comprises a main valve body that includes a body, a seat disposed in the body and a valve body disposed in the body so that the valve body is rotatable through the seat, and that is modulated as a common component part; a stem piercing the body and imparting opening and closing motions to the valve body; an attaching-detaching part disposed at a position at which the stem pierces the body; an operating part disposed on the stem and adapted to operate the valve body; and a coupling part detachably fastened at one end thereof to the attaching-detaching part and mounted at the other end thereof on the operating part for joining the attaching-detaching part and the operating part.